This invention relates to a process for manufacturing laminated safety glass. More particularly, the present invention is concerned with a process for manufacturing laminated safety glass which comprises laminating and bonding a plurality of glass plates through the medium of a film-forming plastisol composed mainly of an epoxy group-containing vinyl chloride resin.
Heretofore, laminated safety glass has been manufactured by a method which comprises interposing a plastic film called an interlayer, including a plasticized polyvinyl butyral, between a plurality of glass plates to laminate the glass plates and subjecting the resulting laminate to deaeration, application of pressure, and heating. However, in the conventional process, in order to remove sodium bicarbonate which has been applied on the surface of the film for the purpose of preventing the self-adhesion between the plastic films themselves, not only a step of washing the film and a step of regulating the moisture of the film after cutting took much time, but also the laminate of the glass plates should be bonded through two steps, i.e., a step of a preliminary contact bonding in a vacuum bag and a step of heat contact bonding in an autoclave, which raises problems such as low productivity and high production cost.
Further, in order to eliminate the step of washing the plastic film composed of plasticized polyvinyl butyral, it was proposed to store and transport the plastic film in a cooled state. However, this method cannot solve the problem on complexity accompanying the handling in a cooled state.
On the other hand, films made of plasticized vinyl chloride, ethylene-vinyl acetate copolymer resin, and ethylene-acrylic acid copolymer resin have been proposed as films free from occurrence of self-adhesion. However, these films do not lead to the solution of the problem on the necessity of many steps, i.e., cutting of the film, adjusting the size of the film with the glass plates, preliminary contact bonding, and main contact bonding.